Organic light emitting diode device

ABSTRACT

Disclosed is an organic light emitting diode device including an anode and a cathode facing each other, an emission layer interposed between the anode and the cathode, and a first hole auxiliary layer interposed between the anode and the emission layer. The first hole auxiliary layer has a higher triplet energy (T 1 ) than the emission layer.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2013-0066110, filed on Jun. 10, 2013,in the Korean Intellectual Property Office, and entitled: “OrganicLight-Emitting Diode Device,” is incorporated by reference herein in itsentirety.

BACKGROUND

1. Field

An organic light emitting diode device is disclosed.

2. Description of the Related Art

Recent requests for reduced size and thickness of a monitor, atelevision, or the like has promoted replacement of a cathode ray tube(CRT) with a liquid crystal display (LCD).

SUMMARY

Embodiments may be realized by providing an organic light emitting diodedevice including an anode and a cathode facing each other, an emissionlayer interposed between the anode and the cathode, and a first holeauxiliary layer interposed between the anode and the emission layer. Thefirst hole auxiliary layer has a higher triplet energy (T1) than that ofthe emission layer.

The emission layer may include a host and a dopant, and0.1 eV+T _(Dopant) <T _(Host) <T _(HAL(1))  (Equation 1)

-   -   wherein, in the Equation 1,    -   T_(Dopant) is a triplet energy (T1) level of the dopant,        T_(Host) is a triplet energy (T1) level of the host, and        T_(HAL(1)) is a triplet energy (T1) level of the first hole        auxiliary layer.

The dopant may be a phosphorescent dopant.

In an embodiment,0.3 eV+T _(Dopant) ≤T _(HAL(1))  (Equation 2)

-   -   wherein, in the Equation 2,    -   T_(Dopant) is a triplet energy (T1) level of the dopant, and        T_(HAL(1)) is a triplet energy (T1) level of the first hole        auxiliary layer.

The triplet energy (T1) of the first hole auxiliary layer may be in arange of about 2.4 to about 3.5 eV, and the triplet energy (T1) of theemission layer may be in a range of about 2.0 to about 3.0 eV.

The emission layer and the first hole auxiliary layer may be adjacent toeach other.

The organic light emitting diode device may further include a secondhole auxiliary layer between the first hole auxiliary layer and theanode.

The first hole auxiliary layer may include a compound having at leastone carbazole group.

The first hole auxiliary layer may include a compound represented by oneof Chemical Formulae 1 to 3:

-   -   wherein, in Chemical Formulae 1 to 3,    -   X is nitrogen (N), boron (B), or phosphorus (P),    -   R¹ to R²² are each independently hydrogen, deuterium, a halogen,        a substituted or unsubstituted C1 to C30 alkyl group, a        substituted or unsubstituted C1 to C30 alkoxy group, a        substituted or unsubstituted C3 to C30 cycloalkyl group, a        substituted or unsubstituted C6 to C30 aryl group, a substituted        or unsubstituted C2 to C30 heteroaryl group, a substituted or        unsubstituted C3 to C30 silyl group, or a combination thereof,    -   R¹ to R²² are present independently or form a fused ring with an        adjacent substituent,    -   Ar¹ to Ar⁴ are each independently hydrogen, a substituted or        unsubstituted C6 to C30 aryl group, a substituted or        unsubstituted C2 to C30 heteroaryl group, or a combination        thereof,    -   Ar¹ to Ar⁴ are present independently or form a fused ring with        an adjacent substituent, and    -   L¹ to L⁵ are each independently a single bond, a substituted or        unsubstituted C1 to C30 alkylene group, a substituted or        unsubstituted C6 to C30 arylene group, a substituted or        unsubstituted C2 to C30 heteroarylene group, or combination        thereof.

The organic light emitting diode device may further include an electronauxiliary layer between the emission layer and the cathode.

In an embodiment, the emission layer may include a host and a dopant,and0.1 eV+EA _(EAL) >EA _(Host)  (Equation 3)0.1 eV+EA _(EAL) >EA _(HAL(1))  (Equation 4)

-   -   wherein, in the Equations 3 and 4,    -   EA_(EAL) is electron affinity of an electron auxiliary layer,        EA_(Host) is electron affinity of the host, and EA_(HAL(1)) is        electron affinity of the first hole auxiliary layer.

The electron auxiliary layer may have electron affinity in a range ofabout 2.4 to about 3.4 eV, the emission layer may have electron affinityin a range of about 2.0 to about 3.2 eV, and the first hole auxiliarylayer may have electron affinity in a range of about 1.8 to about 3.0eV.

The electron auxiliary layer may include a nitrogen-containing ringcompound.

The nitrogen-containing ring may include a substituted or unsubstitutedimidazole, a substituted or unsubstituted triazole, a substituted orunsubstituted tetrazole, a substituted or unsubstituted oxadiazole, asubstituted or unsubstituted oxatriazole, a substituted or unsubstitutedthiatriazole, a substituted or unsubstituted carbazole, a substituted orunsubstituted benzimidazole, a substituted or unsubstitutedbenztriazole, a substituted or unsubstituted pyridine, a substituted orunsubstituted pyrimidine, a substituted or unsubstituted triazine, asubstituted or unsubstituted pyrazine, a substituted or unsubstitutedpyridazine, a substituted or unsubstituted quinoline, a substituted orunsubstituted isoquinoline, a substituted or unsubstituted quinoxaline,a substituted or unsubstituted quinazoline, a substituted orunsubstituted acridine, a substituted or unsubstituted phenanthroline, asubstituted or unsubstituted phenazine, a substituted or unsubstitutedimidazopyridine, tris(8-hydroxyquinolinolato)aluminum, or a combinationthereof.

The electron auxiliary layer may be thinner than the first holeauxiliary layer.

The dopant may be a phosphorescent dopant.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIGS. 1 and 2 illustrate structures of organic light emitting diodedevices according to embodiments.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification.

In addition, “electron affinity (EA)” may be defined as an absolutevalue of energy from a vacuum level to a LUMO energy level in thespecification.

Hereinafter, an organic light emitting diode device according to oneembodiment is described in detail.

FIGS. 1 and 2 illustrate structures of organic light emitting diodedevices according to embodiments.

Referring to FIG. 1, an organic light emitting diode device according toone embodiment includes an anode 10, a cathode 20 facing the anode 10,and an emission layer 50 interposed between the anode 10 and the cathode20, a first hole auxiliary layer 30 interposed between the anode 10 andthe emission layer 50, and an electron auxiliary layer 40 interposedbetween the cathode 20 and the emission layer 50.

A substrate (not shown) may be disposed toward the anode 10 or thecathode 20. The substrate may be formed of, for example, an inorganicmaterial such as glass; an organic material such as polycarbonate,polymethylmethacrylate, polyethyleneterephthalate,polyethylenenaphthalate, polyamide, polyethersulfone, or a combinationthereof; or a silicon wafer.

The anode 10 may be a transparent electrode or an opaque electrode. Thetransparent electrode may be made of, for example, a conductive oxidesuch as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide(SnO₂), zinc oxide (ZnO), or a combination thereof or a thin metal suchas aluminum, silver, or magnesium, while the opaque electrode may bemade of, for example, a metal such as aluminum, silver, or magnesium.

The cathode 20 may include a material having a small work function, sothat electrons may be easily injected into the cathode 20. For example,the material having a small work function may include a metal such asmagnesium, calcium, sodium, potassium, titanium, indium, yttrium,lithium, gadolinium, aluminum silver, tin, lead, cesium, barium, or analloy thereof; or a multi-layer structure material such as LiF/Al,LiO₂/Al, LiF/Ca, LiF/Al, or BaF₂/Ca. The cathode may be a metalelectrode such as, for example, aluminum.

The emission layer 50 may include a blue, red, or green light emittingmaterial. The emission layer 50 may include a host and a dopant. Thedopant may be a phosphorescent dopant.

In an embodiment, the host in the emission layer 50 may be a compound inwhich nitrogen-containing rings, such as, for example, carbazole,azacarbazole, or condensed carbazole, are linked through a single bondor a C6 to C30 arylene group. The compound may be, for example, CBP,mCP, 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine,2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyrazine,9-(4,6-diphenylpyrimidin-2-yl)-3,6-diphenyl-9H-carbazole,9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole,9-phenyl-9′-(pyridin-2-yl)-9H,9′H-3,3′-bicarbazole,9-phenyl-9′-(quinolin-2-yl)-9H,9′H-3,3′-bicarbazole,9-([1,1′-biphenyl]-3-yl)-9′-(pyridin-2-yl)-9H,9′H-3,3′-bicarbazole,9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9′-phenyl-9H,9′H-3,3′-bicarbazole,9-(4,6-diphenylpyrimidin-2-yl)-9′-phenyl-9H,9′H-3,3′-bicarbazole, or5-phenyl-11-(pyridin-2-yl)-5,11-dihydroindolo[3,2-b]carbazole.

The phosphorescent dopant may be a metal complex, and the metal complexmay include a metal of Ir, Pt, or Os.

In an embodiment, the dopant in the emission layer 50 may be, forexample, Ir(ppy)₃, Ir(ppy)₂acac, (piq)₂Ir(acac), or Pt(OEP).

The dopant may be included in an amount of about 3 to about 15 wt %based on 100 wt % of the total weight of the host and the dopant.Maintaining the dopant amount within this range may help preventsaturation of luminary excitons, may help increase luminous efficiency,and may improve roll-off, i.e., efficiency at high brightness levels.

In general, since a phosphorescent host may have a large energy gap,there may be a large barrier for injection of electrons from an electronauxiliary layer. The barrier with the electron auxiliary layer may bedecreased by using a phosphorescent host having an electron transportcharacteristic. However, a smaller energy gap of the host or a largerhole injection barrier may occur.

On the other hand, direct injection of an electron into a phosphorescentlight emitter having a lowest unoccupied molecular orbital (LUMO), notthrough a host, by increasing concentration of the phosphorescent lightemitter may help prevent saturation of a light emitting exciton, mayhelp increase luminous efficiency, and may improve roll-off, i.e.,efficiency at high brightness levels.

In FIG. 1, the first hole auxiliary layer 30 is positioned between theanode 10 and the emission layer 50 and may increase hole mobility. Thefirst hole auxiliary layer 30 may be, for example, a hole transportlayer (HTL). The first hole auxiliary layer 30 may have higher tripletenergy (T1) than the emission layer 50. A triplet energy (T1) differencebetween the first hole auxiliary layer and the emission layer may workas an energy barrier and may help prevent a triplet exciton fromdiffusing into the first hole auxiliary layer, which may help provide anorganic light emitting diode device having a low voltage, highefficiency, and a long life-span.

In an embodiment, the emission layer 50 may include a host and a dopant,and the host and dopant of the emission layer and the triplet energy(T1) of the first hole auxiliary layer may satisfy a relationship of thefollowing Equation 1.0.1 eV+T _(Dopant) <T _(Host) <T _(HAL(1))  (Equation 1)

In the Equation 1,

T_(Dopant) is a triplet energy (T1) level of a dopant of the emissionlayer, T_(Host) is a triplet energy (T1) level of a host of the emissionlayer, and T_(HAL(1)) is the triplet energy (T1) of the first holeauxiliary layer level.

Triplet energy (T1) level of the host may be 0.1 eV higher than tripletenergy (T1) level of the dopant in the emission layer 50. Thus, atriplet exciton formed from the host in the emission layer may beefficiently transported into the triplet energy (T1) level of the dopantin the emission layer, and may result in a high luminous efficiency.

In addition, the triplet energy (T1) of the first hole auxiliary layerlevel may be higher than triplet energy (T1) level of the host anddopant in the emission layer. Thus, a triplet exciton in the emissionlayer may be prevented from diffusing into the first hole auxiliarylayer, may be suppressed from extinction, and may improve luminousefficiency.

In an embodiment, the dopant of the emission layer and the tripletenergy (T1) of the first hole auxiliary layer may satisfy a relationshipof the following Equation 2.0.3 eV+T _(Dopant) ≤T _(HAL(1))  (Equation 2)

In the Equation 2,

T_(Dopant) is a triplet energy (T1) level of a dopant of the emissionlayer, and T_(HAL(1)) is the triplet energy (T1) of the first holeauxiliary layer level.

The triplet energy (T1) of the first hole auxiliary layer level may beabout 0.3 eV higher than the triplet energy (T1) of the dopant in theemission layer level. Thus, a triplet exciton in the emission layer maybe more efficiently prevented from diffusing into the first holeauxiliary layer.

In an embodiment, the dopant of the emission layer and the tripletenergy (T1) of the first hole auxiliary layer may satisfy a relationshipof the following Equation 5.0.2 eV+T _(Dopant) <T _(HAL(1))  (Equation 5)

In an embodiment, the triplet energy (T1) of the first hole auxiliarylayer may be in a range of about 2.4 to about 3.5 eV, and the tripletenergy (T1) of the emission layer may be in a range of about 2.0 toabout 3.0 eV.

Maintaining the triplet energy (T1) of the first hole auxiliary layer 30and the emission layer 50 within these ranges may help efficiently storea triplet exciton in the emission layer inside the emission layer, andmay improve efficiency and life-span of an organic light emitting diodedevice.

In an embodiment, the emission layer and the first hole auxiliary layermay be adjacent to each other.

In an embodiment, the first hole auxiliary layer may smoothly transporta hole and include a compound having at least one carbazole group. Thecarbazole group may help provide excellent hole mobility and thermalstability and, may be included in a compound in the first hole auxiliarylayer to help balance charges in an organic light emitting diode device.

In an embodiment, the first hole auxiliary layer may include a compoundrepresented by one of the following Chemical Formulae 1 to 3.

In the above Chemical Formulae 1 to 3,

X is nitrogen (N), boron (B), or phosphorus (P),

R¹ to R²² are each independently hydrogen, deuterium, a halogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C3to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C2 to C30 heteroaryl group, asubstituted or unsubstituted C3 to C30 silyl group, or a combinationthereof,

R¹ to R²² are present independently or form a fused ring with anadjacent substituent,

Ar¹ to Ar⁴ are each independently hydrogen, a substituted orunsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 toC30 heteroaryl group, or a combination thereof,

Ar¹ to Ar⁴ are present independently or form a fused ring with anadjacent substituent, and

L¹ to L⁵ are each independently a single bond, a substituted orunsubstituted C1 to C30 alkylene group, a substituted or unsubstitutedC6 to C30 arylene group, a substituted or unsubstituted C2 to C30heteroarylene group, or combination thereof.

The first hole auxiliary layer may further include a p-dopant, whichmay, for example, improve conductivity. Examples of the p-dopant includea quinine derivative such as tetracyanoquinone dimethane (TCNQ), or2,3,5,6-tetrafluoro-tetrayano-1,4-benzoquinone dimethane (F4-CTNQ), ametal oxide such as a tungsten oxide or molybdenum oxide, and a cyanogroup-containing compound represented by the following Chemical Formula100. In an embodiment, the p-dopant may include more than two cyanogroups (—CN).

When the first hole auxiliary layer further includes the p-dopant, thep-dopant may be uniformly or non-uniformly dispersed among the layers.

In FIGS. 1 and 2, the electron auxiliary layer 40 is positioned betweenthe cathode 20 and the emission layer 50, and may increase injection andmobility of electrons. The electron auxiliary layer 40 may be, forexample, an electron transport layer (ETL) and/or an electron injectionlayer (EIL).

According to one embodiment, an organic light emitting diode device mayfurther include an electron auxiliary layer 40 between the emissionlayer and the cathode.

In an embodiment, the emission layer may include a host and a dopantsatisfying relationships of the following Equations 3 and 4.0.1 eV+EA _(EAL) >EA _(Host)  (Equation 3)0.1 eV+EA _(EAL) >EA _(HAL(1))  (Equation 4)

In the Equations 3 and 4,

EA_(EAL) is electron affinity of an electron auxiliary layer, EA_(Host)is electron affinity of the host in the emission layer, and EA_(HAL(1))is electron affinity of the first hole auxiliary layer.

When electron affinity of a host in the emission layer 50, electronaffinity of the electron auxiliary layer 40, and electron affinity ofthe first hole auxiliary layer satisfy the relationships of Equations 3and 4, electrons may be easily injected from the cathode and transportedto the emission layer in tiers, which may appropriately balance charges,lower a driving voltage, and improve the life-span of an organic lightemitting diode device.

In an embodiment, the electron auxiliary layer may have electronaffinity in a range of about 2.4 to about 3.4 eV, the emission layer mayhave electron affinity in a range of about 2.0 to about 3.2 eV, and thefirst hole auxiliary layer may have electron affinity in a range ofabout 1.8 to about 3.0 eV.

In an embodiment, the electron auxiliary layer may include anitrogen-containing ring compound. The nitrogen-containing ring may helpthe electron auxiliary layer adjust electron mobility, and may helpappropriately balance charges and improve the life-span and efficiencyof an organic light emitting diode device.

In an embodiment, the nitrogen-containing ring may include a substitutedor unsubstituted imidazole, a substituted or unsubstituted triazole, asubstituted or unsubstituted tetrazole, a substituted or unsubstitutedoxadiazole, a substituted or unsubstituted oxatriazole, a substituted orunsubstituted thiatriazole, a substituted or unsubstituted carbazole, asubstituted or unsubstituted benzimidazole, a substituted orunsubstituted benztriazole, a substituted or unsubstituted pyridine, asubstituted or unsubstituted pyrimidine, a substituted or unsubstitutedtriazine, a substituted or unsubstituted pyrazine, a substituted orunsubstituted pyridazine, a substituted or unsubstituted quinoline, asubstituted or unsubstituted isoquinoline, a substituted orunsubstituted quinoxaline, a substituted or unsubstituted quinazoline, asubstituted or unsubstituted acridine, a substituted or unsubstitutedphenanthroline, a substituted or unsubstituted phenazine, a substitutedor unsubstituted imidazopyridine, tris(8-hydroxyquinolinolato)aluminum,or a combination thereof.

In an embodiment, the nitrogen-containing ring may be, for example,2-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazoleor 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline.

The nitrogen-containing ring indicates a cyclic compound including onlynitrogen, carbon, and hydrogen but may not include “a compound includingother hetero atoms except for nitrogen.”

In addition, “a compound including a benzene ring and anitrogen-containing aromatic ring” and a compound including an electrondonating group (EDG) belong to the cyclic compound including onlynitrogen, carbon, and hydrogen but may not be included in thenitrogen-containing ring.

The compounds may not be included in the nitrogen-containing ring of theelectron auxiliary layer, since the compounds may hinder fast movementof electrons, may make it difficult to balance charges, and maydeteriorate thermal stability and life-span of an organic light emittingdiode device.

In an embodiment, the nitrogen-containing ring may not include acompound represented by the following Chemical Formula a, b, or c.

In an embodiment, the electron auxiliary layer may include an electrontransporting organic compound and a metal-containing material other thanthe nitrogen-containing ring. Examples of the electron transportingorganic compound include DNA (9,10-di(naphthalen-2-yl)anthracene); andan anthracene-based compound such as a compound represented by thefollowing Chemical Formulae 101 and 102.

The metal-containing material may include a Li complex. Examples of theLi complex include lithium quinolate (LiQ), and a compound representedby the following Chemical Formula 103.

In an embodiment, the electron auxiliary layer may be thinner than thefirst hole auxiliary layer. When the electron auxiliary layer is thinnerthan the first hole auxiliary layer, holes and electrons may have abalanced movement, and a hole blocking layer may be omitted, andlife-span deterioration of an organic light emitting diode device may beprevented. In an embodiment, the first hole auxiliary layer may have athickness ranging from about 200 to about 1500 Å, and the electronauxiliary layer may have a thickness ranging from about 50 to about 500Å. In an embodiment, the first hole auxiliary layer may have a thicknessranging from about 300 to about 600 Å, and the electron auxiliary layermay have a thickness ranging from about 200 to about 400 Å.

Hereinafter, an organic light emitting diode device according to oneembodiment is illustrated referring to FIG. 2.

Referring to FIG. 2, an organic light emitting diode device according toanother embodiment like that of the above-described embodiment includesan anode 10 and a cathode 20 facing each other, an emission layer 50interposed between the anode 10 and the cathode 20, a first holeauxiliary layer 30 interposed between the anode 10 and the emissionlayer 50, and an electron auxiliary layer 40 interposed between thecathode 20 and the emission layer 50.

The organic light emitting diode device illustrated in FIG. 2, ascompared to the organic light emitting diode device illustrated in FIG.1, further includes a second hole auxiliary layer 60 interposed betweenthe anode 10 and the first hole auxiliary layer 30.

The second hole auxiliary layer may decrease driving voltage of anorganic light emitting diode device and may improve its life-span,though the organic light emitting diode device may be manufacturedwithout using another organic layer such as an electron blocking layerhaving a deterioration problem.

The second hole auxiliary layer may play a role of injecting andtransporting a hole. The second hole auxiliary layer may include, forexample,N-([1,1′-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine,N-([1,1′-biphenyl]-4-yl)-9,9-diphenyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine,or a compound represented by the following Chemical Formula 4.

For example, an organic light emitting diode device according to oneembodiment may include an anode/a hole injection layer (HIL)/an emissionlayer/a cathode, an anode/a hole injection layer (HIL)/a hole transportlayer (HTL)/an emission layer/an electron transport layer (ETL)/acathode, or an anode/a hole injection layer (HIL)/a hole transport layer(HTL)/an emission layer/an electron transport layer (ETL)/an electroninjection layer (EIL)/a cathode structure. In addition, the organiclight emitting diode device may have a structure of an anode/a functionlayer simultaneously injecting and transporting a hole/an emissionlayer/an electron transport layer (ETL)/a cathode, or an anode/afunction layer simultaneously injecting and transporting a hole/anemission layer/an electron transport layer (ETL)/an electron injectionlayer (EIL)/a cathode. In addition, the organic light emitting diodedevice may have a structure of an anode/a hole transport layer (HTL)/anemission layer/a function layer simultaneously injecting andtransporting an electron/a cathode, an anode/a hole injection layer(HIL)/an emission layer/a function layer simultaneously injecting andtransporting an electron/a cathode, or an anode/a hole injection layer(HIL)/a hole transport layer (HTL)/an emission layer/a function layersimultaneously injecting and transporting an electron/a cathode.

According to one embodiment, an organic light emitting diode device mayhave various structures such as, for example, a front-side lightemitting type, a rear-side light emitting type, or a both side lightemitting type.

According to one embodiment, an organic light emitting diode device maybe mounted in a flat panel display, for example, a passive matrixorganic light emitting diode (OLED) display and an active matrix organiclight emitting diode (OLED) display. When the organic light emittingdiode is mounted in the device active matrix organic light emittingdiode (OLED) display, a lower electrode may be a pixel electrode andelectrically connected to a thin film transistor. In addition, theorganic light emitting diode device according to one embodiment mayinclude a first layer formed by depositing an organic compound accordingto one embodiment or by coating an organic material prepared in form ofa solution in a wet method according to one embodiment.

The following Examples and Comparative Examples are provided in order tohighlight characteristics of one or more embodiments, but it will beunderstood that the Examples and Comparative Examples are not to beconstrued as limiting the scope of the embodiments, nor are theComparative Examples to be construed as being outside the scope of theembodiments. Further, it will be understood that the embodiments are notlimited to the particular details described in the Examples andComparative Examples.

EXAMPLES Example 1

An ITO glass substrate was cut into a size of 50 mm×50 mm×0.5 mm andthen,respectively ultrasonic wave-cleaned in acetone isopropyl alcoholand pure water for 15 minutes and UV ozone represented by ChemicalFormula 5 was vacuum-deposited to form a 1200 Å-thick first holeauxiliary layer on the ITO glass substrate. Subsequently, CBP (SamsungDisplay Co., Ltd.) and 5 wt % of PGDI (Samsung Display Co., Ltd.) werevacuum-deposited on the first hole auxiliary layer to form a 400 Å-thickemission layer. Subsequently, Alq3 (Samsung Display Co., Ltd.) wasvacuum-deposited to form a 300 Å-thick electron auxiliary layer on theemission layer upper. On the electron auxiliary layer, 10 Å-thick LiFand 2000Å-thick Al (a cathode) were sequentially vacuum-deposited,manufacturing an organic light emitting diode device.

Example 2

An organic light emitting diode device was manufactured according to thesame method as Example 1 except for using a second hole auxiliary layerformed of a compound represented by Chemical Formula 4 and a 600Å-thickfirst hole auxiliary layer formed of a compound represented by ChemicalFormula 5 instead of the single first hole auxiliary layer.

Comparative Example 1

An organic light emitting diode device was manufactured according to thesame method as Example 1 except for NPB (Samsung Display Co., Ltd.)instead of the compound represented by Chemical Formula 5 to form thefirst hole auxiliary layer.

Comparative Example 2

An organic light emitting diode device was manufactured according to thesame method as Example 2 except for using a compound represented byChemical Formula 5 instead of the compound represented by ChemicalFormula 4 to form the second hole auxiliary layer and NPB instead of thecompound represented by Chemical Formula 5 to form the first holeauxiliary layer.

Comparative Example 3

An organic light emitting diode device was manufactured according to thesame method as Example 1 except for using a compound represented byChemical Formula 4 instead of the compound represented by ChemicalFormula 5 to form the first hole auxiliary layer.

Evaluation 1

T1 level and electron affinity of the compounds represented by ChemicalFormulae 4 and 5 and compounds represented by CBP, PGD1, NPB, and Alq3are provided in Table 1.

The T1 level and electron affinity were respectively measured by using a77K low temperature PL and CV.

TABLE 1 Electron Materials T1 level affinity Second hole auxiliary layerCompound represented by 2.8 eV 2.0 eV (Example) Chemical Formula 4 Firsthole auxiliary layer Compound represented by 2.7 eV 2.5 eV (Example)Chemical Formula 5 Host of emission layer CBP 2.6 eV 2.6 eV (Example,Comparative Example) Dopant of emission layer PGD1 2.4 eV 3.0 eV(Example, Comparative Example) First and second hole NPB 2.3 eV 2.4 eVauxiliary layers (Comparative Example) Electron auxiliary layer Alq3 2.1eV 3.0 eV (Example, Comparative Example)

Evaluation 2

Driving voltage, current density, efficiency, and life-span LT90 of theorganic light emitting diodes according to Examples 1 and 2 andComparative Examples 1 to 3 were measured, and the results are providedin Table 2.

The efficiency was measured by supplying the organic light emittingdiodes with electricity in a current-voltage system (Kethley SMU 236)and using a luminance meter PR650.

The life-span LT90 indicates a time (hr) taken until the organic lightemitting diodes showed luminance of 90% based on 100% of the initialluminance. (current density: 10 mA/cm²)

TABLE 2 Efficiency Driving voltage Life-span (cd/A) (V) (hr) ComparativeExample 1 100% 100% 100% (reference) Comparative Example 2 103% 102%109% Comparative Example 3 125% 122% 113% Example 1 152%  85% 201%Example 2 165%  74% 187%

Referring to Table 2, the organic light emitting diodes according toExamples 1 and 2 showed a lower driving voltage but improved efficiencyand life-span characteristics compared with the organic light emittingdiode using a single first hole auxiliary layer having a lower T1 levelthan that of a phosphorescent dopant according to Comparative Example 1,the organic light emitting diode using a first hole auxiliary layerhaving a lower T1 level than that of a phosphorescent dopant accordingto Comparative Example 2, the organic light emitting diode using a firsthole auxiliary layer having a higher T1 level than that of aphosphorescent dopant but including no carbazole according toComparative Example 3.

By way of summation and review, an LCD uses a separate backlight, beinga non-emissive device, and may be relatively limited in terms of, forexample, response speed and viewing angle. Use of an organic lightemitting diode device as a display device may provide benefits relativethereto. The organic light emitting diode device is a self-lightemitting display device that may have a wide viewing angle, improvedcontrast, and a fast response time. The organic light emitting diodedevice emits a light when electrons injected from one electrode arecombined with holes injected from the other electrode and form excitonsand emit energy.

One embodiment provides an organic light emitting diode device that mayhave a lowered driving voltage, and improved efficiency and life-spancharacteristics. The organic light emitting diode device using anorganic material efficiently restricting energy excited from an emissionlayer therein may have high efficiency, a low voltage, high luminance,and a long life-span.

Exemplary embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of skill in the art as of thefiling of the present application, features, characteristics, and/orelements described in connection with a particular embodiment may beused singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. An organic light emitting diode device,comprising: an anode and a cathode facing each other, an emission layerinterposed between the anode and the cathode, and a first hole auxiliarylayer interposed between the anode and the emission layer, the firsthole auxiliary layer having a higher triplet energy (T1) than that ofthe emission layer, wherein: the emission layer includes a host and adopant, and0.1 eV+T _(Dopant) <T _(Host) <T _(HAL(1))  (Equation 1) wherein, in theEquation 1 T_(Dopant) is a triplet energy (T1)level of thedopant,T_(Host) is a triplet energy (T1)level of the host, andT_(HAL(1))is a triplet energy (T1) level of the first hole auxiliarylayer.
 2. The organic light emitting diode device as claimed in claim 1,wherein:0.3eV+T _(Dopant) ≤T _(HAL(1))  (Equation 2) wherein, in the Equation 2,T_(Dopant) is a triplet energy (T1) level of the dopant, and T_(HAL(1))is a triplet energy (T1) level of the first hole auxiliary layer.
 3. Theorganic light emitting diode device as claimed in claim 1, wherein: thetriplet energy (T1) of the first hole auxiliary layer is in a range ofabout 2.4 to about 3.5 eV, and the triplet energy (T1) of the emissionlayer is in a range of about 2.0 to about 3.0 eV.
 4. The organic lightemitting diode device as claimed in claim 1, wherein the emission layerand the first hole auxiliary layer are adjacent to each other.
 5. Theorganic light emitting diode device as claimed in claim 1, furthercomprising a second hole auxiliary layer between the first holeauxiliary layer and the anode.
 6. The organic light emitting diodedevice as claimed in claim 1, wherein the first hole auxiliary layerincludes a compound having at least one carbazole group.
 7. The organiclight emitting diode device as claimed in claim 1, wherein the firsthole auxiliary layer includes a compound represented by one of ChemicalFormulae 1 to 3:

wherein, in Chemical Formulae 1 to 3, X is nitrogen (N), boron (B), orphosphorus (P), R¹ to R²² are each independently hydrogen, deuterium, ahalogen, a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C1 to C30 alkoxy group, a substituted orunsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstitutedC6 to C30 aryl group, a substituted or unsubstituted C2 to C30heteroaryl group, a substituted or unsubstituted C3 to C30 silyl group,or a combination thereof, R¹ to R²² are present independently or form afused ring with an adjacent substituent, Ar¹ to Ar⁴ are eachindependently hydrogen, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C2 to C30 heteroaryl group, or acombination thereof, Ar¹ to Ar⁴ are present independently or form afused ring with an adjacent substituent, and L¹ to L⁵ are eachindependently a single bond, a substituted or unsubstituted C1 to C30alkylene group, a substituted or unsubstituted C6 to C30 arylene group,a substituted or unsubstituted C2 to C30 heteroarylene group, orcombination thereof.
 8. The organic light emitting diode device asclaimed in claim 1, further comprising an electron auxiliary layerbetween the emission layer and the cathode.
 9. The organic lightemitting diode device as claimed in claim 8, wherein: the emission layerincludes a host and a dopant, and0.1 eV+EA _(EAL) >EA _(Host)  (Equation 3)0.1 eV+EA _(EAL) >EA _(HAL(1))  (Equation 4) wherein, in the Equations 3and 4, EA_(EAL) is electron affinity of an electron auxiliary layer,EA_(Host) is electron affinity of the host, and EA_(HAL(1)) is electronaffinity of the first hole auxiliary layer.
 10. The organic lightemitting diode device as claimed in claim 9, wherein: the electronauxiliary layer has electron affinity in a range of about 2.4 to about3.4 eV, the emission layer has electron affinity in a range of about 2.0to about 3.2 eV, and the first hole auxiliary layer has electronaffinity in a range of about 1.8 to about 3.0 eV.
 11. The organic lightemitting diode device as claimed in claim 8, wherein the electronauxiliary layer includes a nitrogen-containing ring compound.
 12. Theorganic light emitting diode device as claimed in claim 11, wherein thenitrogen-containing ring includes a substituted or unsubstitutedimidazole, a substituted or unsubstituted triazole, a substituted orunsubstituted tetrazole, a substituted or unsubstituted oxadiazole, asubstituted or unsubstituted oxatriazole, a substituted or unsubstitutedthiatriazole, a substituted or unsubstituted carbazole, a substituted orunsubstituted benzimidazole, a substituted or unsubstitutedbenztriazole, a substituted or unsubstituted pyridine, a substituted orunsubstituted pyrimidine, a substituted or unsubstituted triazine, asubstituted or unsubstituted pyrazine, a substituted or unsubstitutedpyridazine, a substituted or unsubstituted quinoline, a substituted orunsubstituted isoquinoline, a substituted or unsubstituted quinoxaline,a substituted or unsubstituted quinazoline, a substituted orunsubstituted acridine, a substituted or unsubstituted phenanthroline, asubstituted or unsubstituted phenazine, a substituted or unsubstitutedimidazopyridine, tris(8-hydroxyquinolinolato)aluminum, or a combinationthereof.
 13. The organic light emitting diode device as claimed in claim8, wherein the electron auxiliary layer is thinner than the first holeauxiliary layer.
 14. The organic light emitting diode device as claim 1,wherein the dopant is a phosphorescent dopant.
 15. The organic lightemitting diode device as claimed in claim 9, wherein the dopant is aphosphorescent dopant.